Effects of palmitoylethanolamide on immunologically induced histamine, PGD2 and TNFalpha release from canine skin mast cells

Metabolomic Analysis of Follicular Fluid in Normal-Weight Patients with Polycystic Ovary Syndrome

BACKGROUND

This study aimed to examine the differential variations in the metabolic composition of follicular fluid (FF) among normal-weight patients with polycystic ovary syndrome (PCOS) and controls and to identify potential biomarkers that may offer insights into the early identification and management of these patients.

METHODS

We collected FF samples from 45 normal-weight women with PCOS and 36 normal-weight controls without PCOS who were undergoing in vitro fertilization-embryo transfer. An untargeted metabolomic study of collected FF from infertile women was performed using high-performance liquid chromatography-tandem spectrometry (LC-MS). The tendency of the two groups to separate was demonstrated through multivariate analysis. Univariate analysis and variable importance in projection were used to screen out differential metabolites. Metabolic pathway analysis was conducted using the Kyoto Encyclopedia of Genes and Genomes (KEGG), and a diagnostic model was established using the random forest algorithm.

RESULTS

The metabolomics analysis revealed an increase in the expression of 23 metabolites and a decrease in that of 10 metabolites in the FF of normal-weight women with PCOS. According to the KEGG pathway analysis, these differential metabolites primarily participated in the metabolism of glycerophospholipids and the biosynthesis of steroid hormones. Based on the biomarker combination of the top 10 metabolites, the area under the curve value was 0.805. The concentrations of prostaglandin E2 in the FF of individuals with PCOS exhibited an inverse association with the proportion of high-quality embryos (p < 0.05).

CONCLUSIONS

Our research identified a distinct metabolic profile of the FF from normal-weight women with PCOS. The results offer a broader comprehension of the pathogenesis and advancement of PCOS, and the detected differential metabolites could be potential biomarkers and targets for the treatment of PCOS.

Ultramicronized N-palmitoylethanolamine Contributes to Morphine Efficacy Against Neuropathic Pain: Implication of Mast Cells and Glia

BACKGROUND

In the current management of neuropathic pain, in addition to antidepressants and anticonvulsants, the use of opioids is wide, despite their related and well-known issues.

OBJECTIVE

N-palmitoylethanolamine (PEA), a natural fatty-acid ethanolamide whose anti-inflammatory, neuroprotective, immune-modulating and anti-hyperalgesic activities are known, represents a promising candidate to modulate and/or potentiate the action of opioids.

METHODS

This study was designed to evaluate if the preemptive and morphine concomitant administration of ultramicronized PEA, according to fixed or increasing doses of both compounds, delays the onset of morphine tolerance and improves its analgesic efficacy in the chronic constriction injury (CCI) model of neuropathic pain in rats.

RESULTS

Behavioral experiments showed that the preemptive and co-administration of ultramicronized PEA significantly decreased the effective dose of morphine and delayed the onset of morphine tolerance. The activation of spinal microglia and astrocytes, commonly occurring both on opioid treatment and neuropathic pain, was investigated through GFAP and Iba-1 immunofluorescence. Both biomarkers were found to be increased in CCI untreated or morphine treated animals in a PEA-sensitive manner. The increased density of endoneural mast cells within the sciatic nerve of morphine-treated and untreated CCI rats was significantly reduced by ultramicronized PEA. The decrease of mast cell degranulation, evaluated in terms of reduced plasma levels of histamine and N-methyl-histamine metabolite, was mainly observed at intermediate-high doses of ultramicronized PEA, with or without morphine.

CONCLUSION

Overall, these results show that the administration of ultramicronized PEA in CCI rats according to the study design fully fulfilled the hypotheses of this study.

The Effect of Levagen+ (Palmitoylethanolamide) Supplementation on Symptoms of Allergic Rhinitis-A Double-Blind Placebo-Controlled Trial

BACKGROUND

Allergic rhinitis (AR) is an inflammatory, symptomatic disorder stimulated by antigen-specific immunoglobulin E inflammation in response to allergens. Current treatments include the use of corticosteroids and antihistamines to reduce inflammation by preventing histamine release. Palmitoylethanolamide (PEA) is reported to be an alternative treatment, shown to downregulate mast cell activation and increase the synthesis of endocannabinoid 2-Arachidonoylglycerol to reduce histamine and the symptoms of AR.

METHOD

A double-blind, randomised, placebo-controlled clinical trial in which 108 participants presenting with seasonal AR were supplemented with either 350 mg of PEA (Levagen+) or a placebo daily for two weeks. Symptom scores were recorded using the reflective total nasal symptom score (rTNSS) twice a day (morning and evening) for the two weeks, and blood was taken at baseline and week 2.

RESULTS

101 participants completed the study with no baseline group differences. No significant difference was seen between groups for allergy symptoms scores (rTNSS) throughout the 14 days of treatment. A sub-group analysis of participants scoring over four (mild-to-moderate) on the total rTNSS at baseline showed that Levagen+ significantly reduced scores compared to the placebo group. Only 36 participants had full sets of blood taken due to COVID-19. The pathology results showed a significant difference in change from baseline between groups. The Levagen+ group had a significant decrease from baseline in histamine, IL-4, IL-8, IL-10, and TNF-α. The placebo group only had a reduction in IL-4.

CONCLUSION

The results of this study show that Levagen+ can alleviate AR symptoms, resulting in a reduction in histamine and inflammatory markers.

What Is the Role of Palmitoylethanolamide Co-Ultramicronized with Luteolin on the Symptomatology Reported by Patients Suffering from Long COVID? A Retrospective Analysis Performed by a Group of General Practitioners in a Real-Life Setting

Long COVID is a recognized post-viral syndrome characterized by neurological, somatic and neuropsychiatric symptoms that might last for long time after SARS-CoV-2 infection. An ever-growing number of patients come to the observation of General Practitioners complaining of mild or moderate symptoms after the resolution of the acute infection. Nine General Practitioners from the Rome area (Italy) performed a retrospective analysis in order to evaluate the role of the supplementation with Palmitoylethanolamide co-ultramicronized with Luteolin (PEALUT) on neurologic and clinical symptoms reported by their patients after COVID-19 resolution. Supplementation with PEALUT helped to improve all patient-reported symptoms, especially pain, anxiety and depression, fatigue, brain fog, anosmia and dysgeusia, leading to an overall improvement in patients' health status. To our knowledge these are the first data presented on Long COVID patients collected in a territorial setting. Despite their preliminary nature, these results highlight the pathogenetic role of "non-resolving" neuroinflammation in Long COVID development and consequently the importance of its control in the resolution of the pathology and put the focus on the General Practitioner as the primary figure for early detection and management of Long COVID syndrome in a real-life setting. Future randomized, controlled, perspective clinical trials are needed to confirm this preliminary observation.

RT-DOb, a switch gene for the gene pair {Csf1r, Milr1}, can influence the onset of Alzheimer's disease by regulating communication between mast cell and microglia

In biology, homeostasis is a central cellular phenomenon that plays a crucial role in survival. The central nervous system (CNS) is controlled by exquisitely sensitive homeostatic mechanisms when facing inflammatory or pathological insults. Mast cells and microglia play a crucial role in CNS homeostasis by eliminating damaged or unnecessary neurons and synapses. Therefore, decoding molecular circuits that regulate CNS homeostasis may lead to more effective therapeutic strategies that specifically target particular subsets for better therapy of Alzheimer's disease (AD). Based on a computational analysis of a microarray dataset related to AD, the H2-Ob gene was previously identified as a potential modulator of the homeostatic balance between mast cells and microglia. Specifically, it plays such a role in the presence of a three-way gene interaction in which the H2-Ob gene acts as a switch in the co-expression relationship of two genes, Csf1r and Milr1. Therefore, the importance of the H2-Ob gene as a potential therapeutic target for AD has led us to experimentally validate this relationship using the quantitative real-time PCR technique. In the experimental investigation, we confirmed that a change in the expression levels of the RT1-DOb gene (the rat ortholog of murine H2-Ob) can switch the co-expression relationship between Csf1r and Milr1. Furthermore, since the RT1-DOb gene is up-regulated in AD, the mentioned triplets might be related to triggering AD.

Ultramicronized N-Palmitoylethanolamine Regulates Mast Cell-Astrocyte Crosstalk: A New Potential Mechanism Underlying the Inhibition of Morphine Tolerance

Persistent pain can be managed with opioids, but their use is limited by the onset of tolerance. Ultramicronized N-palmitoylethanolamine (PEA) in vivo delays morphine tolerance with mechanisms that are still unclear. Since glial cells are involved in opioid tolerance and mast cells (MCs) are pivotal targets of PEA, we hypothesized that a potential mechanism by which PEA delays opioid tolerance might depend on the control of the crosstalk between these cells. Morphine treatment (30 μM, 30 min) significantly increased MC degranulation of RBL-2H3 cells, which was prevented by pre-treatment with PEA (100 μM, 18 h), as evaluated by β-hexosaminidase assay and histamine quantification. The impact of RBL-2H3 secretome on glial cells was studied. Six-hour incubation of astrocytes with control RBL-2H3-conditioned medium, and even more so co-incubation with morphine, enhanced CCL2, IL-1β, IL-6, Serpina3n, EAAT2 and GFAP mRNA levels. The response was significantly prevented by the secretome from PEA pre-treated RBL-2H3, except for GFAP, which was further upregulated, suggesting a selective modulation of glial signaling. In conclusion, ultramicronized PEA down-modulated both morphine-induced MC degranulation and the expression of inflammatory and pain-related genes from astrocytes challenged with RBL-2H3 medium, suggesting that PEA may delay morphine tolerance, regulating MC-astrocyte crosstalk.

Cannabinoid receptors in the inflammatory cells of canine atopic dermatitis

Background

Atopic dermatitis (AD) is one of the most common cutaneous inflammatory and pruritic diseases in dogs. Considering its multifactorial nature, AD can be a challenging disease to manage, and the therapeutic strategy must often be multimodal. In recent years, research has been moving toward the use of natural products which have beneficial effects on inflammation and itching, and no side effects. Cannabinoid receptors have been demonstrated to be expressed in healthy and diseased skin; therefore, one of the potential alternative therapeutic targets for investigating AD is the endocannabinoid system (ECS).

Objective

To immunohistochemically investigate the expression of the cannabinoid receptor type 2 (CB2R), and the cannabinoid-related receptors G protein-coupled receptor 55 (GPR55), transient receptor potential vanilloid 1 (TRPV1) and ankyrin 1 (TRPA1) in mast cells (MCs), macrophages, dendritic cells (DCs), T cells, and neutrophils of the skin of dogs with AD.

Animals

Samples of skin tissues were collected from eight dogs with AD (AD-dogs).

Materials and methods

The immunofluorescent stained cryosections of the skins of 8 dogs with AD having antibodies against CB2R, GPR55, TRPV1, TRPA1 were semiquantitatively evaluated. The inflammatory cells were identified using antibodies against tryptase (mast cells), ionized calcium binding adaptor molecule 1 (IBA1) (macrophages/DCs), CD3 (T cells), and calprotectin (neutrophils). The proportions of MCs, macrophages/DCs, T cells, and neutrophils expressing CB2R, GPR55, TRPV1 and TRPA1 were evaluated.

Results

The cells of the inflammatory infiltrate showed immunoreactivity (IR) for all or for some of the cannabinoid and cannabinoid-related receptors studied. In particular, MCs and macrophages/DCs showed CB2R-, GPR55-, TRPA1-, and TRPV1-IR; T cells showed CB2R-, GPR55- and TRPA1-IR, and neutrophils expressed GPR55-IR. Co-localization studies indicated that CB2R-IR was co-expressed with TRPV1-, TRPA1-, and GPR55-IR in different cellular elements of the dermis of the AD-dogs.

Conclusions and clinical importance

Cannabinoid receptor 2, and cannabinoid-related receptors GPR55, TRPV1 and TRPA1 were widely expressed in the inflammatory infiltrate of the AD-dogs. Based on the present findings, the ECS could be considered to be a potential therapeutic target for dogs with AD, and may mitigate itch and inflammation.

Palmitoylethanolamide and Related ALIAmides for Small Animal Health: State of the Art

ALIAmides are a family of fatty acid amides whose name comes from their mechanism of action, i.e., the Autacoid Local Injury Antagonism (ALIA). Actually, the ALIAmide parent molecule, palmitoylethanolamide (PEA), is locally produced on demand from a cell membrane precursor in order to control immune-inflammatory cell responses, avert chronic non-resolving inflammation, and limit the resulting clinical signs. ALIAmide sister compounds, such as Adelmidrol and palmitoylglucosamine, share mechanisms of action with PEA and may also increase endogenous levels of PEA. Provided that their respective bioavailability is properly addressed (e.g., through decreasing the particle size through micronization), exogenously administered ALIAmides thus mimic or sustain the prohomeostatic functions of endogenous PEA. The aim of the present paper is to review the main findings on the use of ALIAmides in small animals as a tribute to the man of vision who first believed in this “according-to-nature” approach, namely Francesco della Valle. After briefly presenting some key issues on the molecular targets, metabolism, and pharmacokinetics of PEA and related ALIAmides, here we will focus on the preclinical and clinical studies performed in dogs and cats. Although more data are still needed, ALIAmides may represent a novel and promising approach to small animal health.

Classical and Unexpected Effects of Ultra-Micronized PEA in Neuromuscular Function

Recently, the endocannabinoid system has attracted growing attention from the scientific community for its involvement in homeostatic and pathological processes as they pertains to human physiology. Among the constituents of the endocannabinoid system, the molecule palmitoyl ethanolamide has particularly been studied for its ability to reduce several inflammatory processes involving the central nervous system. Here, we reviewed published literature and summarized the main targets of the palmitoyl ethanolamide, along with its unique possible mechanisms for restoring correct functioning of the central nervous system. Moreover, we have highlighted a less-known characteristic of palmitoyl ethanolamide, namely its ability to modulate the function of the neuromuscular junction by binding to acetylcholine receptors in different experimental conditions. Indeed, there are several studies that have highlighted how ultra-micronized palmitoyl ethanolamide is an interesting nutraceutical support for the treatment of pathological neuromuscular conditions, specifically when the normal activity of the acetylcholine receptor is altered. Although further multicentric clinical trials are needed to confirm the efficacy of ultra-micronized palmitoyl ethanolamide in improving symptoms of neuromuscular diseases, all the literature reviewed here strongly supports the ability of this endocannabinoid-like molecule to modulate the acetylcholine receptors thus resulting as a valid support for the treatment of human neuromuscular diseases.

Genetic Variants of Fatty Acid Amide Hydrolase Modulate Acute Inflammatory Responses to Colitis in Adult Male Mice

Cannabinoids, including cannabis derived phytocannabinoids and endogenous cannabinoids (endocannabinoids), are typically considered anti-inflammatory. One such endocannabinoid is N-arachidonoylethanolamine (anandamide, AEA), which is metabolized by fatty acid amide hydrolase (FAAH). In humans, there is a loss of function single nucleotide polymorphism (SNP) in the FAAH gene (C385A, rs324420), that leads to increases in the levels of AEA. Using a mouse model with this SNP, we investigated how this SNP affects inflammation in a model of inflammatory bowel disease. We administered 2,4,6-trinitrobenzene sulfonic acid (TNBS) intracolonically, to adult male FAAH SNP mice and examined colonic macroscopic tissue damage and myeloperoxidase activity, as well as levels of plasma and amygdalar cytokines and chemokines 3 days after administration, at the peak of colitis. We found that mice possessing the loss of function alleles (AC and AA), displayed no differences in colonic damage or myeloperoxidase activity compared to mice with wild type alleles (CC). In contrast, in plasma, colitis-induced increases in interleukin (IL)-2, leukemia inhibitory factor (LIF), monocyte chemoattractant protein (MCP)-1, and tumor necrosis factor (TNF) were reduced in animals with an A allele. A similar pattern was observed in the amygdala for granulocyte colony stimulating factor (G-CSF) and MCP-1. In the amygdala, the mutant A allele led to lower levels of IL-1α, IL-9, macrophage inflammatory protein (MIP)-1β, and MIP-2 independent of colitis-providing additional understanding of how FAAH may serve as a regulator of inflammatory responses in the brain. Together, these data provide insights into how FAAH regulates inflammatory processes in disease.

Pharmacologic agents directed at the treatment of pain associated with maladaptive neuronal plasticity

INTRODUCTION

The definition of nociplastic pain in 2016 has changed the way maladaptive chronic pain is viewed in that it may emerge without neural lesions or neural disease. Many endogenous and pharmacologic substances are being investigated for their role in treating the pain associated with neuronal plasticity.

AREAS COVERED

The authors review promising pharmacologic agents for the treatment of pain associated with maladaptive neuronal plasticity. The authors then provide the reader with their expert opinion and provide their perspectives for the future.

EXPERT OPINION

An imbalance between the amplification of ascending pain signals and the poor activation of descending inhibitory signals may be at the root of many chronic pain syndromes. The inhibitory activity of noradrenaline reuptake may play a role in neuropathic and nociplastic analgesia. A better understanding of the brain's pain matrix, its signaling cascades, and the complex bidirectional communication between the immune system and the nervous system may help meet the urgent and unmet medical need for safe, effective chronic pain treatment, particularly for pain with a neuropathic and/or nociplastic component.

Cytokine Storm Syndrome in SARS-CoV-2 Infections: A Functional Role of Mast Cells

Cytokine storm syndrome is a cascade of escalated immune responses disposing the immune system to exhaustion, which might ultimately result in organ failure and fatal respiratory distress. Infection with severe acute respiratory syndrome-coronavirus-2 can result in uncontrolled production of cytokines and eventually the development of cytokine storm syndrome. Mast cells may react to viruses in collaboration with other cells and lung autopsy findings from patients that died from the coronavirus disease that emerged in 2019 (COVID-19) showed accumulation of mast cells in the lungs that was thought to be the cause of pulmonary edema, inflammation, and thrombosis. In this review, we present evidence that a cytokine response by mast cells may initiate inappropriate antiviral immune responses and cause the development of cytokine storm syndrome. We also explore the potential of mast cell activators as adjuvants for COVID-19 vaccines and discuss the medications that target the functions of mast cells and could be of value in the treatment of COVID-19. Recognition of the cytokine storm is crucial for proper treatment of patients and preventing the release of mast cell mediators, as impeding the impacts imposed by these mediators could reduce the severity of COVID-19.

Palmitoylethanolamide: A Natural Compound for Health Management

All nations which have undergone a nutrition transition have experienced increased frequency and falling latency of chronic degenerative diseases, which are largely driven by chronic inflammatory stress. Dietary supplementation is a valid strategy to reduce the risk and severity of such disorders. Palmitoylethanolamide (PEA) is an endocannabinoid-like lipid mediator with extensively documented anti-inflammatory, analgesic, antimicrobial, immunomodulatory and neuroprotective effects. It is well tolerated and devoid of side effects in animals and humans. PEA's actions on multiple molecular targets while modulating multiple inflammatory mediators provide therapeutic benefits in many applications, including immunity, brain health, allergy, pain modulation, joint health, sleep and recovery. PEA's poor oral bioavailability, a major obstacle in early research, has been overcome by advanced delivery systems now licensed as food supplements. This review summarizes the functionality of PEA, supporting its use as an important dietary supplement for lifestyle management.

Antioxidant and Anti-inflammatory Effect of Cannabidiol Contributes to the Decreased Lipid Peroxidation of Keratinocytes of Rat Skin Exposed to UV Radiation

There is a great need for compounds with antioxidant and anti-inflammatory properties for protection against UV radiation, which is the most prooxidative physical factor that skin cells are exposed to everyday. Therefore, the aim of the study was to evaluate the mechanism of phytocannabinoid-cannabidiol (CBD) action in vivo on lipid metabolism in keratinocytes of rat skin exposed to UVA/UVB radiation. Our results show that CBD protects keratinocytes against the effects of UVA/UVB radiation by reducing lipid peroxidation products: 4-HNE and 8-isoPGF2α. In addition, CBD significantly increases the level of endocannabinoids, such as anandamide, 2-arachidonylglycerol, and palmitoylethanolamide, and the activation of their receptors CB1/2 or TRPV1. The above changes are due to the protective effect of CBD against the UVA/UVB-induced decrease in the level/activity of superoxide dismutase and the components of the thioredoxin and glutathione systems. CBD also increases the in vivo transcriptional activity of Nrf2 and the expression of its Bach1 inhibitor as well as preventing the UVA/UVB-induced increase in the expression of Nrf2 activators p21, p62, p38, and KAP1 and proinflammatory factors such as NFκB and TNFα. By counteracting oxidative stress and changes in lipid structure in keratinocytes, CBD prevents cellular metabolic disturbances, protecting the epidermis against UV damage.

Pyridostigmine bromide exposure creates chronic, underlying neuroimmune disruption in the gastrointestinal tract and brain that alters responses to palmitoylethanolamide in a mouse model of Gulf War Illness

Gulf War Illness (GWI) is a chronic multisymptom illness that includes gastrointestinal disorders. Although the exact etiology of GWI is unknown, exposure to the drug pyridostigmine bromide (PB) is considered a major factor. Exposure to PB drives enteric neuroinflammation, promotes immunosuppression, and alters physiological functions of the colon in the short term but whether exposure to PB is sufficient to promote long term dysfunction is not known. Here, we tested whether exposure to PB is sufficient to drive long term changes that reflect GWI, and whether the endogenous anti-inflammatory mediator palmitoylethanolamide (PEA) is sufficient to reduce the detrimental effects of PB in the gut and brain of mice. Exposure to PB alone was not sufficient to cause major changes in neuromuscular transmission but did drive major changes by altering the effects of PEA. Calcium imaging data show that the mechanisms responsible include a shift in receptor signaling mediated by TRPV1, endocannabinoids, and peroxisome proliferator-activated receptors alpha (PPARα). Additional mechanisms include the development of glial reactivity and changes in enteric neurochemical coding and survival. PB and PEA caused major shifts in pro-inflammatory cytokines/chemokines in the brain and colon that persisted up to 5 months following exposure. Many of the effects of PB and PEA exhibit significant sex differences. Together, these results highlight novel mechanisms whereby PB promotes long-lasting changes in nervous system and immune function by inducing occult neuroplasticity that is revealed by subsequent exposure to unrelated drugs in a sex dependent manner.

Repurposed drugs and nutraceuticals targeting envelope protein: A possible therapeutic strategy against COVID-19

COVID-19 pandemic caused by SARS-CoV-2 has already claimed millions of lives worldwide due to the absence of a suitable anti-viral therapy. The CoV envelope (E) protein, which has not received much attention so far, is a 75 amino acid long integral membrane protein involved in assembly and release of the virus inside the host. Here we have used artificial intelligence (AI) and pattern recognition techniques for initial screening of FDA approved pharmaceuticals and nutraceuticals to target this E protein. Subsequently, molecular docking simulations have been performed between the ligands and target protein to screen a set of 9 ligand molecules. Finally, we have provided detailed insight into their mechanisms of action related to the varied symptoms of infected patients.

Dietary Supplementation with Palmitoyl-Glucosamine Co-Micronized with Curcumin Relieves Osteoarthritis Pain and Benefits Joint Mobility

Simple Summary

Canine osteoarthritis is a chronic degenerative joint disease and a major cause of elective euthanasia. The disorder increasingly limits joint motion, might cause lameness as well as pain, and impacts quality of life. An unmet need remains for safe and effective therapies for osteoarthritis. Palmitoyl-glucosamine and curcumin are used in animal nutrition. A co-micronized formulation, with the two substances being jointly processed to reduce their particle size and increase the extent to which they can be absorbed, is currently available on the European market. The present study investigated if this formulation could relieve joint pain and benefit mobility. Two well-established rat models of inflammation and osteoarthritis pain were used. Results from the first set of experiments showed that the dietary supplement relieved experimentally induced paw edema, infiltration of inflammatory cells, and decreased sensitivity to painful stimuli (thermal hyperalgesia). In the osteoarthritis model, the supplement proved to protect joint cartilage against degradation and successfully address neuropathic pain (i.e., pain from normally non-painful stimuli). Locomotor function recovered by 45% under supplement administration. The present findings suggest that the dietary supplement with palmitoyl-glucosamine co-micronized with curcumin might help manage osteoarthritis.

Abstract

Chronic mixed pain and orthopedic dysfunction are the most frequently associated consequences of canine osteoarthritis (OA). An unmet need remains for safe and effective therapies for OA. Palmitoyl-glucosamine (PGA) and curcumin are safe and naturally occurring compounds whose use is limited by poor bioavailability. Micronization is an established technique to increase bioavailability. The aim of this study was to investigate if the dietary supplementation with PGA co-micronized with curcumin (PGA-Cur, 2:1 ratio by mass) could limit pathologic process in two well-established rat models of inflammation and OA pain, i.e., subplantar carrageenan (CAR) and knee injection of sodium monoiodoacetate (MIA), respectively. In CAR-injected animals, a single dose of PGA-cur significantly reduced paw edema and hyperalgesia, as well as tissue damage and neutrophil infiltration. The repeated administration of PGA-Cur three times per week for 21 days, starting the third day after MIA injection resulted in a significant anti-allodynic effect. Protection against cartilage damage and recovery of locomotor function by 45% were also recorded. Finally, PGA-cur significantly counteracted MIA-induced increase in serum levels of TNF-α, IL-1β, NGF, as well as metalloproteases 1, 3, and 9. All the effects of PGA-Cur were superior compared to the compounds used singly. PGA-Cur emerged as a useful dietary intervention for OA.

Mast Cell Regulation and Irritable Bowel Syndrome: Effects of Food Components with Potential Nutraceutical Use

Mast cells are key actors in inflammatory reactions. Upon activation, they release histamine, heparin and nerve growth factor, among many other mediators that modulate immune response and neuron sensitization. One important feature of mast cells is that their population is usually increased in animal models and biopsies from patients with irritable bowel syndrome (IBS). Therefore, mast cells and mast cell mediators are regarded as key components in IBS pathophysiology. IBS is a common functional gastrointestinal disorder affecting the quality of life of up to 20% of the population worldwide. It is characterized by abdominal pain and altered bowel habits, with heterogeneous phenotypes ranging from constipation to diarrhea, with a mixed subtype and even an unclassified form. Nutrient intake is one of the triggering factors of IBS. In this respect, certain components of the daily food, such as fatty acids, amino acids or plant-derived substances like flavonoids, have been described to modulate mast cells' activity. In this review, we will focus on the effect of these molecules, either stimulatory or inhibitory, on mast cell degranulation, looking for a nutraceutical capable of decreasing IBS symptoms.

Palmitoylethanolamide and Related ALIAmides: Prohomeostatic Lipid Compounds for Animal Health and Wellbeing

Virtually every cellular process is affected by diet and this represents the foundation of dietary management to a variety of small animal disorders. Special attention is currently being paid to a family of naturally occurring lipid amides acting through the so-called autacoid local injury antagonism, i.e., the ALIA mechanism. The parent molecule of ALIAmides, palmitoyl ethanolamide (PEA), has being known since the 1950s as a nutritional factor with protective properties. Since then, PEA has been isolated from a variety of plant and animal food sources and its proresolving function in the mammalian body has been increasingly investigated. The discovery of the close interconnection between ALIAmides and the endocannabinoid system has greatly stimulated research efforts in this field. The multitarget and highly redundant mechanisms through which PEA exerts prohomeostatic functions fully breaks with the classical pharmacology view of “one drug, one target, one disease”, opening a new era in the management of animals’ health, i.e., an according-to-nature biomodulation of body responses to different stimuli and injury. The present review focuses on the direct and indirect endocannabinoid receptor agonism by PEA and its analogues and also targets the main findings from experimental and clinical studies on ALIAmides in animal health and wellbeing.

Sodium chromo-glycate and palmitoylethanolamide: A possible strategy to treat mast cell-induced lung inflammation in COVID-19

A novel human coronavirus SARS‐CoV‐2 (also referred to as CoV-19) that emerged in late 2019 causes Covid-19 disease a respiratory tract infection which provokes about 4 million deaths per year. Unfortunately, to date, there is no specific antiviral treatment for COVID-19. Mast cells (MCs) are immune cells implicated in the pathogenesis of viral infections, where they mediate inflammation. Microbes, including virus, activate MCs through TLR releasing chemical pro-inflammatory compounds and cytokines. Although, in biomedical literature there are only few reports on MCs activation by SARS-CoV-2 infection. The production of pro-inflammatory cytokines by MC viral activation leads to increase pulmonary inflammation and fibrosis. Sodium Chromo-Glycate (SCG) described as a MC stabilizer, prevents the release of inflammatory chemical compounds, improve mouse survival and respiratory pathological changes in lung viral infection and suppresses inflammation. Furthermore, palmitoylethanolamide (PEA) a nuclear factor agonist, an endogenous fatty acid amide, which exerts a variety of biological effects, related to chronic inflammation and pain, is involved also in MCs homeostasis with an inhibitory and protective effect on the respiratory tract during viral infections. Here, we hypothesize for the first time, that SCG and/or PEA suppress MC activation and pro-inflammatory mediators release, playing an anti-inflammatory therapeutic role in the inflamed lung of patients with COVID-19.

Tolerability of Palmitoylethanolamide in a Pediatric Population Suffering from Migraine: A Pilot Study

Background

Palmitoylethanolamide (PEA) is emerging as a new therapeutic approach in pain and inflammatory conditions, and it has been evaluated in studies on various painful diseases. The aim of this open-label study was to evaluate the efficacy of ultramicronized PEA (umPEA) in the prophylactic treatment of migraine.

Methods

The study included 70 patients with mean age of 10.3 ± 2.7 (24.5% M and 75.5% F). All patients had a diagnosis of migraine without aura (ICHD 3 criteria) and received umPEA (600 mg/day orally) for three months. We compared the attack frequency (AF) and attack intensity at baseline and after three months. Patients were asked to classify the intensity of the attack with a value ranging from 1 to 3, where 1 means mild attack, 2 moderate, and 3 severe attack.

Results

Nine patients discontinued treatment before the target time of 12 weeks. After 3 months of treatment with umPEA, the headache frequency was reduced by >50% per month in 63.9% patients. The number of monthly attacks at T₁ decreased significantly compared with the baseline assessment (from 13.9 ± 7.5 SD of T₀ to 6.5 ± 5.9 SD of T₁; p < 0.001). The mean intensity of the attacks dropped from 1.67 ± 0.6 (T₀) to 1.16 ± 0.5 (T₁) (p < 0.001), and the percentage of patients with severe attacks decreased after treatment (from 8.2% to 1.6%; p < 0.05). The monthly assumptions of drugs for the attack reduced from 9.5 ± 4.4 to 4.9 ± 2.5 (p < 0.001). Only one patient developed mild side effects (nausea and floating).

Conclusions

Our preliminary data show that umPEA administered for three month reduces pain intensity and the number of attacks per month in pediatric patients with migraine. Although the small number of patients and the lack of control group do not allow us to consider these initial results as definitely reliable, they encourage us to expand the sample.

Impact of Nutritional Supplementation on Canine Dermatological Disorders

Nutritional supplements, also known as complementary feeds, are products administered with the aim of furnishing health benefits, regardless of nutritional needs. They have been used since ancient times in veterinary dermatology, and a number of studies have focused on investigating the health benefits of some ingredients found in commercially available complementary feed for dogs. The aim of this paper is to review the literature available on the use of nutritional supplementation for the management of canine skin diseases, critically appraising the clinical efficacy of such interventions and summarizing the current state of knowledge. This review highlights how these feeds can be considered useful in the management of dermatological disorders and outlines their beneficial effects in the prevention of dietary deficiencies and treatment of diseases, alone, or in addition to conventional pharmacological therapy. In recent years, nutritional supplements have found increasing potential application in veterinary medicine, and the scientific proofs of their beneficial effects are described in this review.

Effect of ultramicronized-palmitoylethanolamide and co-micronized palmitoylethanolamide/polydatin on chronic pelvic pain and quality of life in endometriosis patients: An open-label pilot study

Purpose

The aim of the present study was to evaluate the effectiveness of the ultramicronized-palmitoylethanolamide (um-PEA) and co-micronised palmitoylethanolamide/polydatin m(PEA/PLD) in the management of chronic pelvic pain related to endometriosis in patients desiring pregnancy.

Patients and methods

Thirty symptomatic women with laparoscopic diagnosis of endometriosis and pregnancy desire were enrolled. Patients were treated with um-PEA twice daily for 10 days followed by m(PEA/PLD) twice daily for 80 days. Intensity of chronic pelvic pain, dyspareunia, dysmenorrhea, dyschezia, and dysuria were evaluated at baseline, after 10, 30, 60, 90 days and after 30 days from the end of treatment, by VAS. Quality of life and women's psychological well-being were evaluated at baseline and at the end of the treatment after 90 days with 36-Item Short Form Health Survey questionnaire and Symptom Check list-90 questionnaire, respectively. All collected data were analyzed with the non-parametric Wilcoxon test.

Results

At the end of the treatment, all patients showed a significant improvement in chronic pelvic pain, deep dyspareunia, dysmenorrhea, dyschezia, as well as in quality of life and psychological well-being.

Conclusion

In spite of the study's limited sample size and the open-label design, this research suggests the efficacy of um-PEA and m(PEA/PLD) in reducing painful symptomatology and improving quality of life as well as psychological well-being in patients suffering from endometriosis. Additionally, this treatment did not show any serious side effect, proving particularly suitable for women with pregnancy desire and without other infertility factors.

Altered Metabolism of Phospholipases, Diacylglycerols, Endocannabinoids, and N-Acylethanolamines in Patients with Mastocytosis

Background

Mastocytosis is a condition characterized by the expansion and accumulation of mast cells (MCs) in various organs. The symptoms are related to the increased release of MC-derived mediators that exert local and distant effects. MCs are a source and target of phospholipase enzymes (PLs), which catalyze the cleavage of membrane phospholipids releasing lipid mediators (e.g., diacylglycerols (DAGs) and the endocannabinoid (EC) 2-arachidonoylglycerol (2-AG)). To date, there are no data on the role of these lipid mediators in mastocytosis. Here, we analyzed plasma levels of PLA₂, PLC, DAG, ECs, and EC-related N-acylethanolamines in patients with mastocytosis.

Methods

In 23 patients with mastocytosis and 23 healthy individuals, we measured plasma PLA₂ and PLC activities, DAG, 2-AG, anandamide (AEA), palmitoylethanolamide (PEA), and oleoylethanolamide (OEA).

Results

Plasma PLA₂ and PLC activities were increased in mastocytosis patients compared to controls. Concentrations of DAG (18:1 20:4 and 18:0 20:4), two second messengers produced by PLC, were higher in mastocytosis compared to controls, whereas the concentrations of their metabolite, 2-AG, were not altered. AEA was decreased in mastocytosis patients compared to controls; by contrast, AEA congener, PEA, was increased. PLA₂ and PLC activities were increased only in patients with mediator-related symptoms. Moreover, PLC activity was positively correlated with disease severity and tryptase concentrations. By contrast, AEA was negatively correlated with tryptase concentrations.

Conclusions

PLs and some lipid mediators are altered in patients with mastocytosis. Our results may pave the way for investigating the functions of these mediators in the pathophysiology of mastocytosis and provide new potential biomarkers and therapeutic targets.

Effect of dietary supplementation with ultramicronized palmitoylethanolamide in maintaining remission in cats with nonflea hypersensitivity dermatitis: a double-blind, multicentre, randomized, placebo-controlled study

Background

Feline nonflea hypersensitivity dermatitis (NFHD) is a frequent cause of over‐grooming, scratching and skin lesions. Multimodal therapy often is necessary.

Hypothesis/Objectives

To investigate the efficacy of ultramicronized palmitoylethanolamide (PEA‐um) in maintaining methylprednisolone‐induced remission in NFHD cats.

Animals

Fifty‐seven NFHD cats with nonseasonal pruritus were enrolled originally, of which 25 completed all study requirements to be eligible for analysis.

Methods and materials

Cats were randomly assigned to PEA‐um (15 mg/kg per os, once daily; n = 29) or placebo (n = 28) while receiving a 28 day tapering methylprednisolone course. Cats responding favourably to methylprednisolone were then administered only PEA‐um (n = 21) or placebo (n = 23) for another eight weeks, followed by a four week long treatment‐free period. Cats were maintained in the study until relapse or study end, whichever came first. Primary outcome was time to relapse. Secondary outcomes were pruritus Visual Analog Scale (pVAS), SCORing Feline Allergic Dermatitis scale (SCORFAD) and owner Global Assessment Score (GAS).

Results

Mean relapse time was 40.5 days (±7.8 SE) in PEA‐um treated cats (n = 13) and 22.2 days (±3.7 SE) for placebo (n = 12; P = 0.04). On Day 28, the severity of pruritus was lower in the PEA‐um treated cats compared to placebo (P = 0.03). Mean worsening of pruritus at the final study day was lower in the PEA‐um group compared to placebo (P = 0.04), whereas SCORFAD was not different between groups. Mean owner GAS at the final study day was better in the PEA‐um than the placebo‐treated group (P = 0.05).

Conclusion and clinical importance

Ultramicronized palmitoylethanolamide could represent an effective and safe option to delay relapse in NFHD cats.

Cannabinoid Signaling in the Skin: Therapeutic Potential of the "C(ut)annabinoid" System

The endocannabinoid system (ECS) has lately been proven to be an important, multifaceted homeostatic regulator, which influences a wide-variety of physiological processes all over the body. Its members, the endocannabinoids (eCBs; e.g., anandamide), the eCB-responsive receptors (e.g., CB₁, CB₂), as well as the complex enzyme and transporter apparatus involved in the metabolism of the ligands were shown to be expressed in several tissues, including the skin. Although the best studied functions over the ECS are related to the central nervous system and to immune processes, experimental efforts over the last two decades have unambiguously confirmed that cutaneous cannabinoid ("c[ut]annabinoid") signaling is deeply involved in the maintenance of skin homeostasis, barrier formation and regeneration, and its dysregulation was implicated to contribute to several highly prevalent diseases and disorders, e.g., atopic dermatitis, psoriasis, scleroderma, acne, hair growth and pigmentation disorders, keratin diseases, various tumors, and itch. The current review aims to give an overview of the available skin-relevant endo- and phytocannabinoid literature with a special emphasis on the putative translational potential, and to highlight promising future research directions as well as existing challenges.

Clinical applications of palmitoylethanolamide in pain management: protocol for a scoping review

BACKGROUND

Palmitoylethanolamide (PEA) belong to endocannabinoid family, a group of fatty acid amides. PEA has been proven to have analgesic and anti-inflammatory activity and has been used in several controlled studies focused on the management of chronic pain among adult patients with different underlying clinical conditions.

METHODS/DESIGN

A literature search will be performed using PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL). The population will be patients who have chronic pain, the intervention will be the administration of PEA alone or in combination with other drugs for the pain management; the comparison will be the standard therapy in accordance with the current guidelines for the treatment of pain. The Outcomes will be the reduction of pain not restricted to specific scales laying out the pain outcome data described in the included studies.

DISCUSSION

This scoping review aims to describe the clinical applications of the PEA in chronic pain management and its outcome.

SCOPING REVIEW REGISTRATION

Open Science Framework https://osf.io/74tmx/ .

Micronized palmitoylethanolamide reduces joint pain and glial cell activation

OBJECTIVE AND DESIGN

Temporomandibular disorder (TMD) is a common painful condition in the temporomandibular joint (TMJ). Joint inflammation is believed to be a chief cause of pain in patients with TMD, through the release of pro-inflammatory cytokines that induce peripheral sensitization of nerve terminals followed by microglial stimulation.

MATERIALS AND SUBJECT

TMJ was induced in rats with the injection of complete Freund's adjuvant (CFA) emulsion into the left TMJ capsule.

TREATMENT

The present study would assess the effects of micronized palmitoylethanolamide (m-PEA) on glial activation and trigeminal hypersensitivity.

METHODS

Ten mg/kg m-PEA or corresponding vehicle was administered 1 h after CFA and mechanical allodynia and edema were evaluated at 24 and 72 h after CFA injection.

RESULTS

CFA-injected animals showed TMJ edema and ipsilateral mechanical allodynia accompanied by a robust growth in GFAP protein-positive satellite glial cells and activation of resident macrophages in the TG. Moreover, m-PEA administration significantly reduced the degree of TMJ damage and pain, macrophage activation in TG and up-regulation of Iba1.

CONCLUSIONS

The results confirm that m-PEA could represent a novel approach for monitoring pain during trigeminal nerve sensitization.

Effects of Add-On Ultramicronized N-Palmitol Ethanol Amide in Patients Suffering of Migraine With Aura: A Pilot Study

Background: Palmitoyl ethanol amide (PEA) is an endogenously produced substance showing anti-nociceptive effect through both receptor and non-receptor mediated effects at the level of different cellular and tissue sites. This study showed the results of a single blind study that was conducted to evaluate both the safety and the efficacy of ultramicronized PEA (umPEA; 1,200 mg/day) for up 90 days in patients suffering of Migraine with Aura (MA) treated with NSAIDs. Methods: A total of 20 patients, 8 male (33-56-years, average 41.4 ± 7.8) and 12 female (19-61-years, average 38.5 ± 11.9) with MA were admitted to our observation and diagnosed according to ICHD-3 criteria, they received umPEA (1,200 mg/day) in combination with NSAIDs for up to 90 days. They were revaluated at 30, 60, and 90 days after treatment. Results: umPEA administration induced a statistically significant and time dependent pain relief. In particular, these effects were evident at 60 days (male P = 0.01189; female P = <0.01) and they lasted until the end of the study (male P = 0.0066; female P = 0.01473). Conclusion: Although further studies are needed, our findings indicate that in patients suffering of MA treatment with umPEA had good efficacy and safety which candidate this compound as a therapeutic tool in pain migraine management.

A Pharmacological Rationale to Reduce the Incidence of Opioid Induced Tolerance and Hyperalgesia: A Review

Chronic pain is an important health and social problem. Misuse and abuse of opioids in chronic non-cancer pain management seem to be a huge problem, in some countries. This could probably affect the normal use of such analgesics in patients in need of them. Basic and clinical researches should find the solution to mitigate the potential damage. Dysregulation of mast cell and microglia activation plays an important role in the pathogenesis and management of chronic pain. Persistent mast cell activation sensitizes nociceptors and initiates central nervous system inflammatory processes, involving microglial cell activation and sensitization of spinal somatosensory neurons. Exposure of mast cells and microglia to opioids is well known to provoke activation of these non-neuronal immune cell populations, thereby contributing to an exacerbation of pro-inflammatory and pro-nociceptive processes and promoting, over the long-term, opioid-induced hyperalgesia and tolerance. This review is intended to provide the reader with an overview of the role for these non-neuronal cells in opioid-induced chronic pain and tolerance as a consequence of prolonged exposure to these drugs. In addition, we will examine a potential strategy with the aim to modulate opioid-induced over-activation of glia and mast cells, based on endogenous defense mechanisms and fatty acid amide signaling molecules.

Oral Ultramicronized Palmitoylethanolamide: Plasma and Tissue Levels and Spinal Anti-hyperalgesic Effect

Palmitoylethanolamide (PEA) is a pleiotropic lipid mediator with established anti-inflammatory and anti-hyperalgesic activity. Ultramicronized PEA (PEA-um) has superior oral efficacy compared to naïve (non-micronized) PEA. The aim of the present study was two-fold: (1) to evaluate whether oral PEA-um has greater absorbability compared to naïve PEA, and its ability to reach peripheral and central tissues under healthy and local inflammatory conditions (carrageenan paw edema); (2) to better characterize the molecular pathways involved in PEA-um action, particularly at the spinal level. Rats were dosed with 30 mg/kg of [13C]4-PEA-um or naïve [13C]4-PEA by oral gavage, and [13C]4-PEA levels quantified, as a function of time, by liquid chromatography/atmospheric pressure chemical ionization/mass spectrometry. Overall plasma levels were higher in both healthy and carrageenan-injected rats administered [13C]4-PEA-um as compared to those receiving naïve [13C]4-PEA, indicating the greater absorbability of PEA-um. Furthermore, carrageenan injection markedly favored an increase in levels of [13C]4-PEA in plasma, paw and spinal cord. Oral treatment of carrageenan-injected rats with PEA-um (10 mg/kg) confirmed beneficial peripheral effects on paw inflammation, thermal hyperalgesia and tissue damage. Notably, PEA-um down-regulated distinct spinal inflammatory and oxidative pathways. These last findings instruct on spinal mechanisms involved in the anti-hyperalgesic effect of PEA-um in inflammatory pain.

Three-way interaction model to trace the mechanisms involved in Alzheimer's disease transgenic mice

Alzheimer's disease (AD) is the most common cause for dementia in human. Currently, more than 46 million people in the world suffer from AD and it is estimated that by 2050 this number increases to more than 131 million. AD is considered as a complex disease. Therefore, understanding the mechanism of AD is a universal challenge. Nowadays, a huge number of disease-related high-throughput “omics” datasets are freely available. Such datasets contain valuable information about disease-related pathways and their corresponding gene interactions. In the present work, a three-way interaction model is used as a novel approach to understand AD-related mechanisms. This model can trace the dynamic nature of co-expression relationship between two genes by introducing their link to a third gene. Apparently, such relationships cannot be traced by the classical two-way interaction model. Liquid association method was applied to capture the statistically significant triplets which are involved in three-way interaction. Subsequently, gene set enrichment analysis (GSEA) and gene regulatory network (GRN) inference were applied to analyze the biological relevance of the statistically significant triplets. The results of this study suggest that the innate immunity processes are important in AD. Specifically, our results suggest that H2-Ob as the switching gene and the gene pair {Csf1r, Milr1} form a statistically significant and biologically relevant triplet, which may play an important role in AD. We propose that the homeostasis-related link between mast cells and microglia is presumably controlled with H2-Ob expression levels as a switching gene.

Ultramicronized palmitoylethanolamide counteracts the effects of compound 48/80 in a canine skin organ culture model

BACKGROUND

Ultramicronized palmitoylethanolamide (PEA-um) has been reported to reduce pruritus and skin lesions in dogs with moderate atopic dermatitis and pruritus.

HYPOTHESIS/OBJECTIVES

A canine ex vivo skin model was used to investigate the ability of PEA-um to counteract changes induced by compound 48/80, a well-known secretagogue that causes mast cell degranulation.

ANIMALS

Normal skin was obtained from three donor dogs subjected to surgery for reasons unrelated to the study.

METHODS

Cultured skin biopsy samples in triplicate were treated with 10 and 100 μg/mL compound 48/80, without or with 30 μM PEA-um. Mast cell (MC) degranulation, histamine release into the culture medium, local microvascular dilatation, epidermal thickness, keratinocyte proliferation and epidermal differentiation markers were evaluated.

RESULTS

Exposure of the skin organ culture to PEA-um 24 h before and 72 h concomitantly to compound 48/80 resulted in a significant decrease of degranulating MCs. PEA-um also reduced the histamine content in the culture medium by half, although the effect did not reach statistical significance. PEA-um significantly counteracted vasodilation induced by 100 μg/mL compound 48/80. Finally, PEA-um alone did not induce changes in epidermal thickness, differentiation markers, keratinocyte proliferation, MC density and/or degranulation.

CONCLUSIONS AND CLINICAL IMPORTANCE

Collectively, these results support the protective action PEA-um on the skin of dogs undergoing allergic changes.

The pharmacology of palmitoylethanolamide and first data on the therapeutic efficacy of some of its new formulations

Palmitoylethanolamide (PEA) has emerged as a potential nutraceutical, because this compound is naturally produced in many plant and animal food sources, as well as in cells and tissues of mammals, and endowed with important neuroprotective, anti-inflammatory and analgesic actions. Several efforts have been made to identify the molecular mechanism of action of PEA and explain its multiple effects both in the central and the peripheral nervous system. Here, we provide an overview of the pharmacology, efficacy and safety of PEA in neurodegenerative disorders, pain perception and inflammatory diseases. The current knowledge of new formulations of PEA with smaller particle size (i.e. micronized and ultra-micronized) when given alone or in combination with antioxidant flavonoids (i.e. luteolin) and stilbenes (i.e. polydatin) is also reviewed.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

Palmitoylethanolamide, a Natural Retinoprotectant: Its Putative Relevance for the Treatment of Glaucoma and Diabetic Retinopathy

Retinopathy is a threat to the eyesight, and glaucoma and diabetes are the main causes for the damage of retinal cells. Recent insights pointed out a common pathogenetic pathway for both disorders, based on chronic inflammation. Palmitoylethanolamide (PEA) is an endogenous cell protective lipid. Since its discovery in 1957 as a biologically active component in foods and in many living organisms, around 500 scientific papers have been published on PEA's anti-inflammatory and neuron-protective properties. PEA has been evaluated for glaucoma, diabetic retinopathy, and uveitis, pathological states based on chronic inflammation, respiratory disorders, and various pain syndromes in a number of clinical trials since the 70s of 20th century. PEA is available as a food supplement (PeaPure) and as diet food for medical purposes in Italy (Normast, PeaVera, and Visimast). These products are notified in Italy for the nutritional support in glaucoma and neuroinflammation. PEA has been tested in at least 9 double blind placebo controlled studies, among which two studies were in glaucoma, and found to be safe and effective up to 1.8 g/day, with excellent tolerability. PEA therefore holds a promise in the treatment of a number of retinopathies. We discuss PEA as a putative anti-inflammatory and retinoprotectant compound in the treatment of retinopathies, especially related to glaucoma and diabetes.

Efficacy of ultra-micronized palmitoylethanolamide in canine atopic dermatitis: an open-label multi-centre study

BACKGROUND

Palmitoylethanolamide is a naturally occurring bioactive lipid, produced on-demand by damage-exposed cells. Palmitoylethanolamide is documented to counteract inflammation, itch and pain.

OBJECTIVE

The aim of this 8-week study was to evaluate the efficacy of oral ultra-micronized palmitoylethanolamide (PEA-um) in dogs with moderate atopic dermatitis.

ANIMALS

Clinicians from 39 veterinary clinics enrolled 160 dogs with nonseasonal atopic dermatitis and moderate pruritus.

METHODS

This was a multi-centre open-label study. On days 0 (D0) and 56 (D56), owners evaluated pruritus with a Visual Analog Scale (VAS) and completed a validated Quality of Life (QoL) questionnaire. Veterinarians assessed the severity of skin lesions using the Canine Atopic Dermatitis Lesion Index (CADLI).

RESULTS

Mean pruritus VAS score decreased from 5.7 ± 0.08 cm (range 3.8-7.9 cm) to 3.63 ± 0.19 cm (range 0.1-9.2 cm) (P < 0.0001). At D56, 58% of dogs showed a greater than 2 cm reduction from baseline and 30% showed an absent-to-very mild pruritus (VAS ≤ 2 cm). Mean total CADLI at D56 decreased significantly (P < 0.0001); in 62% of dogs this score reached a value in the remission range (≤5). Mean total QoL score was significantly decreased (P < 0.0001) with 45% of dogs reaching QoL values described for healthy animals. Tolerability was good-to-excellent with only four dogs reporting treatment associated reversible adverse events.

CONCLUSIONS AND CLINICAL IMPORTANCE

PEA-um appears to be effective and safe in reducing pruritus and skin lesions, and in improving QoL in dogs with moderate atopic dermatitis and moderate pruritus.

Interaction between the protective effects of cannabidiol and palmitoylethanolamide in experimental model of multiple sclerosis in C57BL/6 mice

Cannabinoids (CBs) have recently been approved to exert broad anti-inflammatory activities in experimental models of multiple sclerosis (MS). It has been demonstrated that these compounds could also have effects on neurodegeneration, demyelination, and autoimmune processes occurring in the pathology of MS. However, the clinical use of CBs is limited by their psychoactive effects. Among cannabinoid compounds, cannabidiol (CBD) and palmitoylethanolamide (PEA) have no psychotropic activities. We induced experimental autoimmune encephalomyelitis (EAE), a model of MS, by injecting myelin oligodendrocyte glycoprotein (MOG) to C57BL/6 mice. We assessed the effects of CBD, PEA, and co-administration of CBD and PEA on neurobehavioral scores, immune cell infiltration, demyelination, axonal injury, and the expression of inflammatory cytokines by using histochemistry methods and real-time RT-PCR. Treatment with either CBD (5mg/kg) or PEA (5mg/kg) during disease onset reduced the severity of the neurobehavioral scores of EAE. This effect of CBD and PEA was accompanied by diminished inflammation, demyelination, axonal damage and inflammatory cytokine expression while concurrent administration of CBD (5mg/kg) and PEA (5mg/kg) was not as effective as treatment with either drug per se. These results suggest that, CBD and PEA, non-psychoactive CBs, attenuate neurobehavioral deficits, histological damage, and inflammatory cytokine expression in MOG-immunized animals. However, there is an antagonistic interaction between CBD and PEA in protection against MOG-induced disease.

N-palmitoylethanolamine and N-acetylethanolamine are effective in asteatotic eczema: results of a randomized, double-blind, controlled study in 60 patients

BACKGROUND

Asteatotic eczema (AE) is characterized by itchy, dry, rough, and scaling skin. The treatments for AE are mainly emollients, usually containing urea, lactic acid, or a lactate salt. N-palmitoylethanolamine (PEA) and N-acetylethanolamine (AEA) are both endogenous lipids used as novel therapeutic tools in the treatment of many skin diseases. The purpose of this study was to compare a PEA/AEA emollient with a traditional emollient in the treatment of AE.

METHODS

A monocentric, randomized, double-blind, comparative trial was conducted in 60 AE patients to evaluate and compare the efficacy of the two emollients. The level of skin dryness among the subjects ranged from mild to moderate. The subjects' skin barrier function and the current perception threshold were tested for 28 days by clinical scoring and bioengineering technology.

RESULTS

The results showed that, although some aspects were improved in both groups, the group using the emollient containing PEA/AEA presented a better skin surface change in capacitance. However, the most impressive finding was the ability of the PEA/AEA emollient to increase the 5 Hz current perception threshold to a normal level after 7 days, with a significant difference between values at baseline and after 14 days. A current perception threshold of 5 Hz was positively and significantly correlated with skin surface hydration and negatively correlated with transepidermal water loss in the PEA/AEA emollient group.

CONCLUSION

Compared with traditional emollients, regular application of a topical PEA/AEA emollient could improve both passive and active skin functions simultaneously.

Palmitoylethanolamide in CNS health and disease

The existence of acylethanolamides (AEs) in the mammalian brain has been known for decades. Among AEs, palmitoylethanolamide (PEA) is abundant in the central nervous system (CNS) and conspicuously produced by neurons and glial cells. Antihyperalgesic and neuroprotective properties of PEA have been mainly related to the reduction of neuronal firing and to control of inflammation. Growing evidence suggest that PEA may be neuroprotective during CNS neurodegenerative diseases. Advances in the understanding of the physiology and pharmacology of PEA have potentiated its interest as useful biological tool for disease management. Several rapid non-genomic and delayed genomic mechanisms of action have been identified for PEA as peroxisome proliferator-activated receptor (PPAR)-α dependent. First, an early molecular control, through Ca(+2)-activated intermediate- and/or big-conductance K(+) channels opening, drives to rapid neuronal hyperpolarization. This is reinforced by the increase of the inward Cl(-) currents due to the modulation of the gamma aminobutyric acid A receptor and by the desensitization of the transient receptor potential channel type V1. Moreover, the gene transcription-mediated mechanism sustains the long-term anti-inflammatory effects, by reducing pro-inflammatory enzyme expression and increasing neurosteroid synthesis. Overall, the integration of these different modes of action allows PEA to exert an immediate and prolonged efficacious control in neuron signaling either on inflammatory process or neuronal excitability, maintaining cellular homeostasis. In this review, we will discuss the effect of PEA on metabolism, behavior, inflammation and pain perception, related to the control of central functions and the emerging evidence demonstrating its therapeutic efficacy in several neurodegenerative diseases.

Increased levels of palmitoylethanolamide and other bioactive lipid mediators and enhanced local mast cell proliferation in canine atopic dermatitis

BACKGROUND

Despite the precise pathogenesis of atopic dermatitis (AD) is unknown, an immune dysregulation that causes Th2-predominant inflammation and an intrinsic defect in skin barrier function are currently the two major hypotheses, according to the so-called outside-inside-outside model. Mast cells (MCs) are involved in AD both by releasing Th2 polarizing cytokines and generating pruritus symptoms through release of histamine and tryptase. A link between MCs and skin barrier defects was recently uncovered, with histamine being found to profoundly contribute to the skin barrier defects.Palmitoylethanolamide and related lipid mediators are endogenous bioactive compounds, considered to play a protective homeostatic role in many tissues: evidence collected so far shows that the anti-inflammatory effect of palmitoylethanolamide depends on the down-modulation of MC degranulation.Based on this background, the purpose of the present study was twofold: (a) to determine if the endogenous levels of palmitoylethanolamide and other bioactive lipid mediators are changed in the skin of AD dogs compared to healthy animals; (b) to examine if MC number is increased in the skin of AD dogs and, if so, whether it depends on MC in-situ proliferation.

RESULTS

The amount of lipid extract expressed as percent of biopsy tissue weight was significantly reduced in AD skin while the levels of all analyzed bioactive lipid mediators were significantly elevated, with palmitoylethanolamide showing the highest increase.In dogs with AD, the number of MCs was significantly increased in both the subepidermal and the perifollicular compartments and their granule content was significantly decreased in the latter. Also, in situ proliferation of MCs was documented.

CONCLUSIONS

The levels of palmitoylethanolamide and other bioactive lipid mediators were shown to increase in AD skin compared to healthy samples, leading to the hypothesis that they may be part of the body's innate mechanisms to maintain cellular homeostasis when faced with AD-related inflammation. In particular, the increase may be considered a temptative response to down-regulating the observed elevation in the number, functionality and proliferative state of MCs in the skin of AD dogs. Further studies are warranted to confirm the hypothesis.

Characterization of endocannabinoid-mediated induction of myeloid-derived suppressor cells involving mast cells and MCP-1

Endocannabinoids are lipid-signaling molecules found in the nervous system; however, their precise role in the periphery is unclear. In the current study, we observed that a single i.p. administration of AEA caused rapid induction of MDSCs. The MDSCs contained a mixture of granulocytic and monocytic subtypes and expressed Arg-1 and iNOS. The MDSCs suppressed T cell proliferation in vitro and used iNOS to mediate their effect. Moreover, adoptive transfer of MDSCs led to suppression of mBSA-induced DTH. Through the use of pharmacological inhibition, as well as genetic knockout mice, we found that the induction of MDSCs by AEA was CB1-dependent. The induction of MDSCs by AEA was reduced significantly in mast cell-deficient mice, while maintained in LPS-insensitive mice, showing that the induction of MDSCs by AEA was dependent, at least in part, on mast cells and independent of TLR4. Chemokine analysis of AEA- treated WT mice showed an early spike of MCP-1, which was decreased in Kit(W/W-sh) mice, showing a role of mast cells in the secretion of MCP-1 in response to AEA. Also, use of antibodies against MCP-1 or mice deficient in MCP-1 confirmed the role played by MCP-1. Interestingly, MCP-1 played a significant role in the induction of monocytic but not granulocytic MDSCs. Our studies demonstrate for the first time that endocannaboinids activate CB1 on mast cells to induce MCP-1, which facilitates recruitment of monocytic MDSCs.

Palmitoylethanolamide: A Natural Body-Own Anti-Inflammatory Agent, Effective and Safe against Influenza and Common Cold

Palmitoylethanolamide (PEA) is a food component known since 1957. PEA is synthesized and metabolized in animal cells via a number of enzymes and exerts a multitude of physiological functions related to metabolic homeostasis. Research on PEA has been conducted for more than 50 years, and over 350 papers are referenced in PubMed describing the physiological properties of this endogenous modulator and its pharmacological and therapeutical profile. The major focus of PEA research, since the work of the Nobel laureate Levi-Montalcini in 1993, has been neuropathic pain states and mast cell related disorders. However, it is less known that 6 clinical trials in a total of nearly 4000 people were performed and published last century, specifically studying PEA as a therapy for influenza and the common cold. This was done before Levi-Montalcini's clarification of PEA's mechanism of action, analyzing the role of PEA as an anti-inflammatory agent. We will review in depth these studies, as the results support the effectiveness and safety of PEA in flu and respiratory infections.

Glia and mast cells as targets for palmitoylethanolamide, an anti-inflammatory and neuroprotective lipid mediator

Glia are key players in a number of nervous system disorders. Besides releasing glial and neuronal signaling molecules directed to cellular homeostasis, glia respond also to pro-inflammatory signals released from immune-related cells, with the mast cell being of particular interest. A proposed mast cell-glia communication may open new perspectives for designing therapies to target neuroinflammation by differentially modulating activation of non-neuronal cells normally controlling neuronal sensitization-both peripherally and centrally. Mast cells and glia possess endogenous homeostatic mechanisms/molecules that can be upregulated as a result of tissue damage or stimulation of inflammatory responses. Such molecules include the N-acylethanolamines, whose principal family members are the endocannabinoid N-arachidonoylethanolamine (anandamide), and its congeners N-stearoylethanolamine, N-oleoylethanolamine, and N-palmitoylethanolamine (PEA). A key role of PEA may be to maintain cellular homeostasis when faced with external stressors provoking, for example, inflammation: PEA is produced and hydrolyzed by microglia, it downmodulates mast cell activation, it increases in glutamate-treated neocortical neurons ex vivo and in injured cortex, and PEA levels increase in the spinal cord of mice with chronic relapsing experimental allergic encephalomyelitis. Applied exogenously, PEA has proven efficacious in mast cell-mediated experimental models of acute and neurogenic inflammation. This fatty acid amide possesses also neuroprotective effects, for example, in a model of spinal cord trauma, in a delayed post-glutamate paradigm of excitotoxic death, and against amyloid β-peptide-induced learning and memory impairment in mice. These actions may be mediated by PEA acting through "receptor pleiotropism," i.e., both direct and indirect interactions of PEA with different receptor targets, e.g., cannabinoid CB2 and peroxisome proliferator-activated receptor-alpha.

Mast cell-glia axis in neuroinflammation and therapeutic potential of the anandamide congener palmitoylethanolamide

Communication between the immune and nervous systems depends a great deal on pro-inflammatory cytokines. Both astroglia and microglia, in particular, constitute an important source of inflammatory mediators and may have fundamental roles in central nervous system (CNS) disorders from neuropathic pain and epilepsy to neurodegenerative diseases. Glial cells respond also to pro-inflammatory signals released from cells of immune origin. In this context, mast cells are of particular relevance. These immune-related cells, while resident in the CNS, are able to cross a compromised blood-spinal cord and blood-brain barrier in cases of CNS pathology. Emerging evidence suggests the possibility of mast cell-glia communication, and opens exciting new perspectives for designing therapies to target neuroinflammation by differentially modulating the activation of non-neuronal cells normally controlling neuronal sensitization-both peripherally and centrally. This review aims to provide an overview of recent progress relating to the pathobiology of neuroinflammation, the role of glia, neuro-immune interactions involving mast cells and the possibility that glia-mast cell interactions contribute to exacerbation of acute symptoms of chronic neurodegenerative disease and accelerated disease progression, as well as promotion of pain transmission pathways. Using this background as a starting point for discussion, we will consider the therapeutic potential of naturally occurring fatty acid ethanolamides, such as palmitoylethanolamide in treating systemic inflammation or blockade of signalling pathways from the periphery to the brain in such settings.